Search results
Results from the WOW.Com Content Network
In most situations it is impractical to achieve escape velocity almost instantly, because of the acceleration implied, and also because if there is an atmosphere, the hypersonic speeds involved (on Earth a speed of 11.2 km/s, or 40,320 km/h) would cause most objects to burn up due to aerodynamic heating or be torn apart by atmospheric drag. For ...
But the maximal velocity on the new orbit could be approximated to 33.5 km/s by assuming that it reached practical "infinity" at 3.5 km/s and that such Earth-bound "infinity" also moves with Earth's orbital velocity of about 30 km/s. The InSight mission to Mars launched with a C 3 of 8.19 km 2 /s 2. [5]
The increase per meter would be 4.8 J/kg; this rate corresponds to one half of the local gravity of 9.5 m/s 2. The speed is 7.8 km/s, the net delta-v to reach this orbit is 8.0 km/s. Taking into account the rotation of the Earth, the delta-v is up to 0.46 km/s less (starting at the equator and going east) or more (if going west).
Several of these were once in equilibrium but are no longer: these include Earth's moon ... Escape velocity: km/s: 2.38 2.56 2.025 2.741 2.440 0.159 0.239 0.393 0.510
So if a comet approaching Earth (effective radius ~6400 km) with a velocity of 12.5 km/s (the approximate minimum approach speed of a body coming from the outer Solar System) is to avoid a collision with Earth, the impact parameter will need to be at least 8600 km, or 34% more than the Earth's radius.
This is greater than the Δv required for an escape orbit: 10.93 − 7.73 = 3.20 km/s. Applying a Δv at the Low Earth orbit (LEO) of only 0.78 km/s more (3.20−2.42) would give the rocket the escape velocity, which is less than the Δv of 1.46 km/s
In order to leave the Solar System, the probe needs to reach the local escape velocity. Escape velocity from the sun without the influence of Earth is 42.1 km/s. In order to reach this speed, it is highly advantageous to use as a boost the orbital speed of the Earth around the Sun, which is 29.78 km/s.
One classical thermal escape mechanism is Jeans escape, [1] named after British astronomer Sir James Jeans, who first described this process of atmospheric loss. [2] In a quantity of gas, the average velocity of any one molecule is measured by the gas's temperature, but the velocities of individual molecules change as they collide with one another, gaining and losing kinetic energy.